development of models of acoustic-gravity waves in the upper atmosphere (overview)

We present the results of studies of acoustic-gravity waves (AGWs) in the upper atmosphere of the Earth. The work has been mainly aimed at studying the peculiarities of atmospheric AGWs in the atmosphere based on the theoretical models taking into account the properties of the real atmosphere and the model verification based on spacecraft measurement data. This overview includes the main results obtained by the authors over the last years. The details of the calculations are contained in the authors' works cited here. The possibility of the existence of new types of evanescent acoustic-gravity waves in the isothermal atmosphere is theoretically predicted. A previously unknown inelastic mode and a family of evanescent pseudo-modes are discussed. The peculiarities of the propagation of the acoustic-gravity waves at the boundary of two isothermal half-spaces with different temperatures are studied in dependence of their spectral parameters and the magnitude of the temperature jump at the boundary. The peculiarities of the interaction of acoustic-gravity waves with spatially inhomogeneous atmospheric flows are also studied. It is analyzed the observed effects that are a consequence of such interaction. The influence of vertical non-isothermality on propagation of acoustic-gravity waves including the modification of acoustic and gravitational regions depending on the temperature is studied. On the basis of modified Navier-Stokes and heat transfer equations, the influence of attenuation on the propagation of acoustic-gravity waves in the atmosphere is analyzed. It is also considered the attenuation of various types of evanescent acoustic-gravity waves in the atmosphere. It is shown that the rotation of the atmosphere leads to the modification of the continuous spectrum of evanescent acoustic-gravity waves with frequencies greater than the Coriolis parameter.